Re: CULT: Leaf Spot-Boron Deficiency?

Anner writes...
>Reading in IRIS: AN IDEAL HARDY PERENNIAL, published by the AIS in 1947, I
>came upon the suggestion (p. 88) that leafspot may be related to a Boron
>deficiency in the soil.
In the apocrypha of iris literature there is a strong belief, (myth?) that
iris grown in urban areas where coal smoke is at high levels are usually
completely free of leaf spot. (could they be referencing 'auld reeky'?)
My chemistry is not up to the task of enumerating the principal elements of
coal soot, but I do know that boron is a constituent. Boron is unique in
that it is required for growth in almost all plants but concentrations only
slightly higher than required for normal growth are injurious.
Obviously this hypothesis is not verifiable in most areas of the modern world!
Cheers,
Mike Lowe mlowe@worldiris.com http://www.worldiris.com